Radio signaling



April 23, 1929.

M. LATOUR RADIO SIGNALING Original Filed Aug 19 1921 L AMPLI PIER FREQUENCY awvanfoz MARIUS LMOUR Patented Apr. 23, 1929.

UNITED STATES PATENT OFFICE.

MARIUS LATOUB, OF PARIS, FRANCE, ASSIGNOR TO LATOUR CORPORATION, OFJER- SEY CITY, NEW JERSEY, A CGRPOBATION OF DELAWARE. i

RADIO SIGNALING.

Application filed August 19, 1921, Serial No. 493,669, and in France August 2, 1917. Renewed August 31, 1928.

(GRANTED UNDER THE IROVISIONS OF THE ACT OF MARCH 8, 1921, 41 STAT. L, 1318.)

This invention particularly relates to i1nprovements in the arrangements described in my U. S. Patent No. 1,405,523, dated Febru ary 7, 1922, and to the arrangements described in my copending U. S.applications, Serial No. 213,080, filed July 2, 1918 and Serial No. 193,670, filed August 19, 1921.

In vacuum tube an'iplitiers such as disclosed in the U. S. patent mentioned, and particularly in reversible amplifiers such as those described in the applications mentioned, it often happens that high frequency oscillations occur notwithstanding the fact that apparatus is provided for amplifying low frequency currents. Due to the presence of this unexpected condition the apparatus will be noisy, will distort when amplifying or will not amplify at all.

In accordance with the present invention this condition is avoided by preventing the existence of an electrical connection between the input and output sides of the apparatus.

This is accomplished by establishing an acoustical connection in the low frequency circuits between the plate circuit of one tube and the grid circuit of the next tube, instead of utilizing the usual electrical coupling through a transformer. By acoustical conncction, I refer for example, to the well known connection or coupling which may be established by means of mechanical relays comprising a telephone receiver and a microphone.

Referring to the single-figure drawing, which is a schematic diagram of a preferred embodiment of my invention, a source of radio frequencyis connected to the input of the detector, the output of said detector being connected to the input of an audio frequency amplifier. The output of the audio frequency amplifier is connected to a sound reproductive device 1, the sound waves emanating therefrom impinging on a diaphragm of the microphone device 2. The microphone device 2 is connected to the input side of another audio frequency amplifier A whose output side may be connected to a sound reproductive device 3 as shown. I

It will be seen that only low frequency oscillatlons may occur in the audio frequency amplifier A,, because the diaphragm of the receiver which establishes the connection or coupling vibrates only in response to low frequencies. If the receiver is at a sullicient distance from the transmitter no capacity effect can occur between the mput and output of y what I claim 1s:

1. A multi-stage cascade audio frequency amplifier, each stage comprising a vacuum tube and associated circuits, and a one-way acoustical coupling means between two adjacent stages for electrically isolating portions of said amplifier. M

9. An audio amplifier cmnprising a plurality of stages, each stage including a vacuum tube prm'idcd with an input circuit and an output circuit, and a one Way acoustical coupling means between the output circuit of one vacuum tube and the input circuit of an adjacent vacuum tube whereby said stages are electrically isolated. I

MARIUS LATOUR. 

